Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to the field of injection molding apparatus, and more particularly to an internal latch system for an injection mold.
2. Description of the Related Art
In injection molds that include multiple plates there are many uses for a device that allows opening of the mold at parting lines while selected plates are prevented from moving. Devices that are presently available do not allow the plates to be returned mechanically without possibility of damage to the mold if a plate moves out of sequence.
As a consequence of the foregoing situation, there has existed a longstanding need for a new and improved internal latch system for an injection mold, and the provision of such a construction is a stated objective of the present invention.
Briefly stated, the present invention provides an internal latch for an injection mold that allows opening of the mold at parting lines while selected plates are locked in position and prevented from moving. The system includes an external bushing, an internal bushing that carries cam retainers, and a locking pin. The system may be used in an injection mold having in sequence a stationary plate, a stripper plate and a support plate. The external bushing is secured to the support plate, the internal bushing is secured to the stripper plate, and the locking pin is secured to the stationary plate. The cam retainers selectively engage grooves in the external bushing to lock the stripper plate from moving with respect to the support plate when the locking pin is inserted into the internal bushing beyond the location of the cam retainers. When the locking pin is extracted from the internal bushing, the cam retainers are free to move inwardly thus unlocking the stripper plate from the support plate.